1. Field of the Invention
The present invention relates to the design of an improved delivery device for applying two-component adhesives such as fibrin sealant. More particularly, the delivery device includes needles for separately ejecting two adhesive components (such as fibrinogen and thrombin) so that the ejected components are impinged and mixed, and thereby clotted to seal a wound, stop bleeding or the like.
2. Description of the Related Art
Blood is coagulated through several steps of chain reactions between various proteins in blood. The final stage of the coagulation cascade can be depicted as the following biochemical reactions between fibrinogen, factor XIII, and thrombin. 
As shown in the above reactions, fibrinogen is proteolytically cleaved into fibrin monomer by thrombin, and factor XIII, which is a calcium dependent enzyme, is proteolytically cleaved by thrombin in the presence of calcium ion into an activated form (Factor XIIIa). The activated factor XIII converts the noncovalently assembled fibrin monomer into cross-linked and covalently bonded fibrin fiber having a three-dimensional network.
Fibrin sealant (also called fibrin glue or fibrin adhesive), which is a representative example of the two-component biological sealant, exploits the final stage of the coagulation cascade. The main ingredient of the first component includes fibrinogen and factor XIII, and the main ingredient of the second component includes thrombin and calcium chloride that works as a catalyst for the coagulation reaction. By mixing the two components just prior to use, and applying the mixed components on a wound of a patient, the two components undergo a rapid coagulation to seal the wound.
FIG. 1a is a drawing for illustrating the mixed state of the first component including fibrinogen and the second component including thrombin, and F and T in FIG. 1a denote heterogeneous components including fibrinogen and thrombin, respectively. As shown in FIG. 1a, the fibrin glue coagulation process is a heterogeneous reaction between layers or drops of the two components F and T, thus the coagulation reaction is carried out on the surfaces of the layers or drops of the components. FIG. 1b is a schematic diagram for illustrating the coagulating process of fibrinogen and thrombin. In FIG. 1b, f, t, XIII and Ca denote fibrinogen, thrombin, factor XIII and calcium ion, respectively. As shown in FIG. 1b, the first coagulation layer is formed on the boundary of the layers or drops of the two components T and F, and the unreacted components would be trapped in pockets between these initially solidified layers. Further coagulation continues only by the diffusion of the fibrinogen f or thrombin t through the solidified layer formed on their boundary. Since the boundary prevents the diffusion of the thrombin and/or fibrinogen, and the diffusion coefficients of the proteins is generally low compared to organic or inorganic molecules, the further coagulation is retarded due to the gel-type solidified layer formed on the boundary. Thus, the high degree of mixing of the two components is important for applying the fibrin sealant to seal a wound, stop bleeding or the like. In addition, the two components should be preserved separately prior to be applied to a patient for preventing coagulation of the two components before use or in delivery device.
Various types of delivery devices for applying the two components fibrin sealant to a patient are disclosed in prior arts. For example, delivery devices using a pressurized gas to eject the sealant components are disclosed in U.S. Pat. Nos. 5,582,595, 5,665,067, 5,759,167 and 5,887,755. The delivery devices have problems in that intricate parts have to be used to precisely control the pressure of the ejected components, a sanitized gas supplying system is required, and the components are sprayed to the target area only in aerosol form.
There are other types of the delivery system having internal mixing parts such as mixing needle, cell, well, or syringe tube (U.S. Pat. Nos. 4,359,049, 4,978,336, 4,735,616, 4,979,942, 5,104,375 and 5,116,315, 5,174,653). An exemplary device of this kind is disclosed in U.S. Pat. No. 4,735,616, and is shown in FIG. 2. As shown in FIG. 2, the fibrin sealant delivery system includes a pair of syringe body 10 and 20 supported by a connecting member 30, and piston type plungers 15 and 25 are provided for actuating the components from the syringe bodies 10 and 20. The upper ends of the piston type plunger 15 and 25 are connected by a connecting clip member 40 for simultaneously pressing the plungers 15 and 25. The delivery system includes a connecting head 70 which is attachable to the bodies 10 and 20, and includes conveying channels 61. A mixing needle 74 is attached to the other end of the connecting head 70. The conveying channels 61 are spirally twisted to enhance the mixing efficiency of the two components in the mixing needle 74, and the components mixed in the mixing needle 74 are ejected and applied to a treatment site.
However, in this device, the volume of the mixing needle 74 is generally small, and the retention time of the components in the mixing needle 74 is not enough for the sufficient mixing of the components. The mixing efficiency of the delivery systems can be improved if the flow rate for inducing turbulence of the components becomes higher. However, if the flow rate gets higher, there is possibility of forming undesirable bubbles during the flow of fluid in the device. Other drawback of the device is the clotting of the device due to the coagulation of the two components in the mixing needle. If the flow of the sealant is temporarily stopped during surgery, the clotting of device is more liable to happen.
U.S. Pat No. 5,174,653 discloses the delivery device having a connecting head containing a spirally molded element to produce turbulences in the stream of the conveyed components. FIG. 3 is a cross sectional plan view of the connecting head containing the spirally molded element. As shown in FIG. 3, the two components T and F which are in-flowed into the connecting head 70 are completely mixed due to the turbulence produced by the spirally molded elements 72. However, the two components in the connecting head 70 are easily coagulated and clots the connecting head 70 which prevent further use of the device. In addition, due to the complex configuration of the spirally molded element 72, it is difficult and expensive to produce the device.
To overcome the drawbacks, U.S. Pat. Nos. 4,874,368, 5,474,540, 5,368,563 and 5,759,171 disclose delivery devices for conveying and ejecting the two components through separate passages. U.S. Pat. No 4,874,368 disclose delivery devices having two parallel syringe tubes and needles for containing and ejecting each component. U.S. Pat. Nos. 5,368,563, 5,474,540, and 5,759,171 disclose delivery devices having means for ejecting the components in a swirling pattern for sufficient mixing of the components. However, the means generally have complex channels which have to be drilled, molded or otherwise formed, thus it is difficult and expensive to produce the swirling means due to its complex structure.
The fibrin sealant delivery system of U.S. Pat. No. 4,874,368 is shown in FIG. 4. As shown in FIG. 4, The fibrin sealant delivery system includes a pair of syringe body 10 and 20, a connecting member 30, piston type plungers 15 and 25, and a connecting clip member 40 which have the same functions with the corresponding members in FIG. 2. In FIG. 4, reference numeral 70 is a hollow sleeve for holding the needles 61 together. As shown in FIG. 4, the delivery system includes the separate syringe bodies 10 and 20, and needles 61 for separately delivering the two components to the target site. Thus, the fibrin glue sealant cannot be mixed in the system, and the clotting of the syringes 10 and 20 or needles 61 can be partly prevented. However, in this case, since the end portions of the needles 61 are adjacent to each other, it is possible for one component ejected from a needle 61 can be attached to the end of the other needle 61. Thus, when the delivery devices is not in use in surgery, the clogging would happen at the ends of the needles 61, which prevent further use of the delivery device. In addition, since the two needles 61 are in parallel, the mixing of the two ejected components is insufficient, and the coagulation of the two components on a treatment site is possibly incomplete.
It is accordingly an object of the present invention to provide a new two-component sealant delivery device which permits rapid and complete blending of the two components.
It is another object of the present invention to provide a two-component sealant delivery device which prevents clogging of the needles or syringes of the device.
It is yet another object of the present invention to provide a sealant delivery device which has simple structure and is produced with low cost.
A further object of the present invention is to provide a two-component sealant delivery device for blending and mixing the two components outside of the device and enlarging the application area of the mixed two components.
To accomplish these and other advantages, the present invention provides a delivery device for applying two-component adhesives to a treatment site, which includes a pair of syringe bodies for storing a first and a second adhesive components, respectively, a pair of plungers associated with the pair of syringe bodies for expelling the first and the second component from the pair of syringe bodies; and a pair of needles connected to the syringe bodies for providing separate passages for the components. The pair of needles have distal end surfaces which are apart from each other with a predetermined distance, and faced each other with an angle in the range of 10xc2x0 to less than 180xc2x0.
The present invention also provides a delivery device for applying two-component adhesives to a treatment site including a pair of needles having needle ends for ejecting the components so that the ejected component are impinged and redirected to the treatment site.
The present invention further provides a delivery device for applying two-component adhesives to a treatment site including a pair of needles connected to the syringe bodies for providing separate passages for the components, wherein the needles includes needle bodies which are connected to the syringes and bent to be held together, and needle ends which extends from the needle bodies, and bent outwardly and then inwardly along with the direction of ejected components to apart the distal end surfaces of the needle ends.